WO2020244561A1

WO2020244561A1 - Deviation correction data packet transmission and reception method, system and device

Info

Publication number: WO2020244561A1
Application number: PCT/CN2020/094235
Authority: WO
Inventors: 赵元一
Original assignee: 千寻位置网络有限公司
Priority date: 2019-06-04
Filing date: 2020-06-03
Publication date: 2020-12-10
Also published as: JP7210781B2; KR102658345B1; CN112034498A; CN112034498B; KR20220011720A; JP2022535882A

Abstract

A positioning technique, and a deviation correction data packet transmission and reception method, system and device. The method comprises: a server distributing a first deviation correction data packet to a user terminal in a first information period, the number of bits occupied by quality factor data in the first deviation correction data packet being A (step 101); and the server distributing a second deviation correction data packet to the user terminal in at least one consecutive information period following the first information period, the number of bits occupied by quality factor data in the second deviation correction data packet being B, where A > B, and each of A and B is a positive integer (step 102). The invention can greatly reduce the volume of SSR information to be transmitted based on the existing RTCM format, thereby significantly reducing transmission costs and time.

Description

Method, system and device for sending and receiving differential correction data message

Technical field

This application relates to positioning technology, in particular to the sending and receiving technology of differential correction data messages.

Background technique

At present, there are many internationally adopted encoding formats for broadcasting high-precision correction data messages through satellites. For example, the existing satellite FM forwarding standard RTCM format to the receiving end, although real-time positioning and correction can be achieved, but the amount of data is huge and the transmission It takes a long time, and the single transmission data of SSR1-3 is in the order of millions of bits (see page 1 for reference); the existing compact SSR technology standard adopted by QZSS is only applicable to Japan, and most of the formats are not In line with China's domestic positioning requirements, SSR1-3 has a single transmission data level of one million bits (see page 2 for reference). However, none of the formats in the specific PPP-RTK technology solves the compression problem of the information coding format under the large demand for high concurrency and low delay, so that the channel redundancy increases and the utilization rate decreases.

Summary of the invention

The purpose of this application is to provide a method, system and device for sending and receiving differentially corrected data messages, which greatly reduces the amount of SSR information transmission based on the original RTCM format, and saves a lot of transmission cost and time.

This application discloses a method for sending a differential correction data message, including:

The server broadcasts the first differential correction data message to the user terminal in the first information period, and the number of bits occupied by the quality factor data in the first differential correction data message is A;

At least one continuous information period after the first information period, the server broadcasts a second differential correction data message to the user terminal, the bits occupied by the quality factor data in the second differential correction data message The number of bits is B, where A>B, and A and B are positive integers.

In a preferred example, the header of the differential correction data message includes an identification bit for indicating whether the number of bits occupied by the quality factor data in the message is A bit or B bit.

In a preferred example, the first differential correction data message further includes satellite identification data, and first, second, third and fourth model polynomial coefficient data, wherein the quality in the first differential correction data message The factor data corresponds to the first, second, third, and fourth model polynomial coefficient data in the first differential correction data message;

The second differential correction data message further includes satellite identification data, first, second, third and fourth model polynomial coefficient data, wherein the quality factor data in the second differential correction data message corresponds to the The second difference corrects the first, second, third and fourth model polynomial coefficient data in the data message.

In a preferred example, the quality factor data in the first differential correction data message is full quality factor data, and the quality factor data in the second differential correction data message is incremental quality factor data.

In a preferred example, the quality factor data in the second differential correction data message is an increment of the current quality factor data.

In a preferred example, before the server broadcasts the first differential correction data message to the user terminal in the first information period, the method further includes:

The server receives the state space representation method correction data broadcast by the satellite in each information cycle;

The server performs encoding format calculation on the state space representation method correction data to generate corresponding quality factor data in the first differential correction data message or quality factor data in the second differential correction data message.

This application also discloses a system for sending differential correction data messages, including:

The first sending module is configured to broadcast a first differential correction data message to the user terminal in a first information period, and broadcast a second differential data message to the user terminal at least one continuous information period after the first information period A corrected data message, where the number of bits occupied by the quality factor data in the first differentially corrected data message is A, and the number of bits occupied by the quality factor data in the second differentially corrected data message is B, and A >B, A and B are positive integers.

In a preferred example, it further includes a first receiving module and a calculation module;

The first receiving module is configured to receive state space representation method correction data broadcast by satellites in each information period, and the calculation module is configured to perform encoding format calculation on the state space representation method correction data to generate the corresponding first The quality factor data in the differential correction data message or the quality factor data in the second differential correction data message.

This application also discloses a method for receiving a differential correction data message, including:

The user terminal receives the differential correction data message from the server;

The user terminal determines whether the quality factor data received in the differential correction data message is A bit or B bit, where A>B, and A and B are positive integers;

If the received quality factor data is an A bit, update the current quality factor data to the A bit quality factor data;

If the received quality factor data is B bits, the current quality factor data is updated according to the current quality factor data and the B-bit quality factor data.

In a preferred example, in the step of the user terminal determining whether the quality factor data received in the differential correction data message is A bit or B bit, the user terminal according to the message of the differential correction data message The identification bit in the header identifies whether the quality factor data is A bit or B bit.

In a preferred example, the A-bit quality factor data is full quality factor data, and the B-bit quality factor data is incremental quality factor data.

In a preferred example, the B-bit quality factor data is an increment of the current quality factor data.

This application also discloses a receiving system for differentially corrected data messages, including:

The second receiving module is used to receive the differential correction data message from the server;

A judgment module, configured to determine whether the quality factor data received in the differential correction data message is A bit or B bit, where A>B, and A and B are positive integers;

The processing module is configured to update the current quality factor data to the A bit quality factor data if the received quality factor data is A bit, and if the received quality factor data is B bit, then according to The current quality factor data and the B-bit quality factor data update the current quality factor data.

In a preferred example, the judgment module is further configured to identify whether the quality factor data is an A bit or a B bit according to the identification bit in the header of the data message by the differential correction.

This application also discloses a device for sending differential correction data messages, including:

Memory for storing computer executable instructions; and,

The processor is used to implement the steps in the sending method described above when executing the computer-executable instructions.

The present application also discloses a computer-readable storage medium. The computer-readable storage medium stores computer-executable instructions. When the computer-executable instructions are executed by a processor, the steps in the sending method described above are realized.

This application also discloses a device for receiving differential correction data messages, including:

Memory for storing computer executable instructions; and,

The processor is used to implement the steps in the receiving method described above when executing the computer-executable instructions.

The application also discloses a computer-readable storage medium. The computer-readable storage medium stores computer-executable instructions. When the computer-executable instructions are executed by a processor, the steps in the receiving method described above are implemented.

In the implementation of this application, the data format of the regional atmospheric correction data in the PPP-RTK positioning technology is encoded in a flexible and arranging manner, so as to achieve the problem of compressing the overall data volume.

In the implementation of this application, firstly, based on the original RTCM format, the arrangement and transmission method of quality factor data in the differential correction data message format is optimized, and the full quality factor data and incremental quality factor data are combined to perform corresponding differences. Correct the broadcasting of data messages. Among them, the transmission of incremental quality factor data greatly reduces the transmission volume of the differential correction data message, which saves a lot of transmission cost and time, and because the data is streamlined, the error caused by the long transmission distance and large fading of the synchronous satellite signal is reduced. The bit rate increases. Furthermore, the full quality factor data is broadcasted regularly or irregularly, so that the user terminals newly joining the service can obtain the original data (full data). Therefore, while reducing the amount of information compression, the user accuracy of each user terminal is also guaranteed.

Furthermore, for the QZSS coding system, the technical indicators have been redefined according to various needs, so that the corrected information can conform to different geographical conditions or land areas and atmospheric conditions while maintaining high accuracy. For example, to optimize the layout according to the geographical situation of China, firstly, the allocation method of QI's Class and Value can be optimized according to the region. In order to ensure a certain resolution in the map, follow the calculation result in formula (1) The data in Table 2 can be reversed, but in practical applications, the whole of China does not need such a design, because the north-south span of China is large, and the atmospheric activity in the northern region is not intense, so fine resolution is not needed. Part of the data is relatively flat and can be quantified in a small range, and the atmospheric activity in southern China is intense. Only a small part of the area can adopt this design; and in the case of ensuring a certain resolution in the SSR correction data, it needs to be based on the current area The upper and lower limits of the ionospheric activity in the sky are set, otherwise the positioning effect will not be achieved, and even the opposite effect will be produced. Because the activity of the ionosphere itself is strongly related to latitude, the closer to the equator the ionosphere is approximately active, leading to corrections The larger the range and the smaller the resolution, the result is an increase in data volume. In the implementation of this application, the technical indicators (correction range, grid range, etc.) are redefined according to China's national conditions, so that the correction information conforms to China's geographic conditions, land area and atmospheric conditions while maintaining high accuracy.

A large number of technical features are recorded in the specification of this application, which are distributed in various technical solutions. If all possible combinations of technical features (ie, technical solutions) of this application are to be listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above invention content of this application, the various technical features disclosed in the various embodiments and examples below, and the various technical features disclosed in the drawings can be freely combined with each other to form Various new technical solutions (these technical solutions are deemed to have been recorded in this specification), unless such a combination of technical features is technically infeasible. For example, in one example, the feature A+B+C is disclosed, and in another example, the feature A+B+D+E is disclosed, and the features C and D are equivalent technical means that play the same role. Technically, just choose It can be used once and cannot be used at the same time. Feature E can be combined with feature C technically. Then, the solution of A+B+C+D should not be regarded as documented due to technical infeasibility, and A+B+ The C+E plan should be deemed to have been documented.

Description of the drawings

FIG. 1 is a schematic flowchart of a method for sending a differential correction data message according to a first embodiment of the present application;

Fig. 2 is a schematic diagram of associated bits in a message header according to an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a system for transmitting a differentially corrected data message according to a second embodiment of the present application;

4 is a schematic flowchart of a method for receiving a differentially corrected data message according to a third embodiment of the present application;

Fig. 5 is a schematic structural diagram of a receiving system for a differentially corrected data message according to a fourth embodiment of the present application.

Detailed ways

In the following description, many technical details are proposed in order to enable readers to better understand this application. However, those of ordinary skill in the art can understand that even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in this application can be realized.

Explanation of some concepts:

Global Navigation Satellite System (Global Navigation Satellite System), abbreviated as: GNSS.

Beidou Navigation Satellite System (BDS navigation Satellite system), abbreviated as: BDS.

State Space Representation (State Space Representation), referred to as SSR.

Precise Point Positioning, referred to as PPP.

Carrier phase real-time dynamic difference (Real Time Kinematic), referred to as RTK.

Transmission Control/Internet Protocol (Transmission Control/Internet Protocol), referred to as TCP/IP.

Internet-based RTCM data transmission protocol (Networked Transport of RTCM via Internet), abbreviated as: NTRIP.

Radio Technical Commission for Maritime Services (Radio Technical Commission for Maritime Services), referred to as RTCM.

Quasi-Zenith Satellite System (Quasi-Zenith Satellite System), abbreviated as: QZSS.

Total Electron Content Unit (Total Electron Content Unit), referred to as TECU.

Quality Indicator (Quality Indicator), referred to as QI.

In order to make the objectives, technical solutions, and advantages of the present application clearer, the implementation manners of the present application will be further described in detail below in conjunction with the accompanying drawings.

The first embodiment of the present application relates to a method for sending a differential correction data message. The process is shown in Fig. 1. The method includes the following steps:

Initially, step 101 is executed, the server broadcasts a first differential correction data message to the user terminal in the first information period, and the number of bits occupied by the quality factor data (QI _A ) in the first differential correction data message is A.

Optionally, before step 101, the following sub-steps A and B are also included: start sub-step A: the server receives the state space representation method correction data broadcast by the satellite in each information period. Sub-step B is then performed: the server performs encoding format calculation on the state space representation method correction data to generate the corresponding first differential correction data message or the second differential correction data message.

After that, step 102 is executed. At least one consecutive information period after the first information period, the server broadcasts a second differential correction data message to the user terminal, and the quality factor data in the second differential correction data message The number of bits occupied by (QI _B ) is B, where A>B, and A and B are positive integers.

Generally, the first and second differential correction data messages are formatted data blocks. Optionally, it includes a start line describing the message; optionally, it includes a header block (or message header/header) containing attributes; optionally, it includes a body containing data Part (or body).

In an embodiment, the first and second differential correction data packets respectively include header and body.

Optionally, the body of the first differential correction data message contains A-bit quality factor data, and the body of the second differential correction data message contains B-bit quality factor data. Optionally, the body of the first differential correction data message further includes satellite identification data, first, second, third and fourth model polynomial coefficient data (C ₀₀ , C ₀₁ , C ₁₀ , C ₁₁ ), The quality factor data (QI _A ) in the first differential correction data message corresponds to the first, second, third, and fourth model polynomial coefficient data in the first differential correction data message. Optionally, the body of the second differential correction data message further includes: satellite identification data, first, second, third and fourth model polynomial coefficient data C ₀₀ , C ₀₁ , C ₁₀ , C ₁₁ , where the The quality factor data (QI _B ) in the second differential correction data message corresponds to the first, second, third, and fourth model polynomial coefficient data in the second differential correction data message.

Optionally, the headers of the first and second differential correction data messages include identification bits for indicating whether the number of bits occupied by the quality factor data in the message is A bits or B bits. Figure 2 is a schematic diagram of the associated bits of a message header (ie header) in a specific embodiment of the present application. The 1-bit identification bit "STEC TYPE (the name is just an example, there is no restriction in actual applications)" added to the header is to enable the user (at the user terminal) to actively know that the "quality factor data" is 6 bits when using it Or 1bit; specifically, the function of "STEC TYPE" is when this field is "1", it means that the "Quality Factor Data (QI _A )" in the SSR information following this header is 1 bit in length; similarly, when this field is "0" indicates that the "quality factor data (QI _A )" in the SSR information following this message header is 6 bits in length. 1bit and 6bits in Fig. 2 are only specific examples of the quality factor data length, which can be adjusted according to the actual application, for example, it can be 2bits or 6bits, 3bits and 6bits, etc.

Optionally, the A-bit quality factor data in the first differential correction data message is full quality factor data, and the B-bit quality factor data in the second differential correction data message is incremental quality factor data.

There are many ways for the server to broadcast the first or second differential correction data message. Optionally, the server broadcasts the first differential correction data message at a fixed period, for example, every N information periods is a fixed period, that is, the first and Nth information periods are broadcast in full, and the remaining broadcast increments. Optionally, the server broadcasts the first differential correction data packet from time to time, for example, the first information cycle is broadcast in full, the second and third information cycles are broadcast in increments, the fourth information cycle is broadcast in full, and the fifth and sixth information cycles are broadcast in full. , The seventh information cycle broadcasts the increment, the eighth information cycle broadcasts the full amount, the ninth, tenth, eleventh, and the twelfth information cycle broadcasts the increment, etc.; for example, the first information cycle is fully broadcast, the second and third Information cycle broadcast increment, the fourth information cycle is fully broadcast, the fifth, sixth, seventh, eighth, ninth information cycle is broadcast increment, the tenth information cycle is fully broadcast, the eleventh, twelfth, tenth 3. The fourteenth and fifteenth information cycle broadcast increments,... etc. The quality factor data of the A bit (or the full amount) in the first differential correction data message is broadcast regularly or irregularly, so that the newly added user terminal can obtain the original amount. Therefore, not only the user accuracy of the user is guaranteed, but also a certain amount of information compression is guaranteed.

Optionally, the B-bit quality factor data in the second differential correction data message is an identifier indicating the current quality factor data change. For example, the B bit is "1bit", where 1bit is an identifier 1 or 0 indicating the current quality factor data change, the identifier 1 indicates a decrease, and the identifier 0 indicates an increase. In another embodiment, the B-bit quality factor data in the second differential correction data message is an increment of the current quality factor data.

The second embodiment of the present application relates to a system for transmitting differentially corrected data messages. The structure of the system is shown in FIG. 3. The system for transmitting differentially corrected data messages includes a first transmitting module. The first sending module is configured to broadcast a first differential correction data message to a user terminal in a first information period, and at least one continuous information period after the first information period to broadcast second differential correction data to the user terminal Message, wherein the number of bits occupied by quality factor data (QI _A ) in the first differential correction data message is A, and the number of bits occupied by quality factor data (QI _B ) in the second differential correction data message The number is B, and A>B, A and B are positive integers.

Optionally, the body of the first differential correction data message contains A-bit quality factor data, and the body of the second differential correction data message contains B-bit quality factor data. Optionally, the body of the first differential correction data message further includes: satellite identification data, first, second, third, and fourth model polynomial coefficient data C ₀₀ , C ₀₁ , C ₁₀ , C ₁₁ , where the first differential correction data packets QI _a quality factor data corresponding to the first differential correction of the first, second, third and fourth data model polynomial coefficients and data packets. Optionally, the body of the second differential correction data message further includes: satellite identification data, first, second, third and fourth model polynomial coefficient data C ₀₀ , C ₀₁ , C ₁₀ , C ₁₁ , where the The quality factor data QI _B in the second differential correction data message corresponds to the first, second, third, and fourth model polynomial coefficient data in the second differential correction data message.

Optionally, the headers of the first and second differential correction data messages include identification bits for indicating whether the number of bits occupied by the quality factor data in the message is A bits or B bits. Figure 2 is a schematic diagram of the associated bits of a message header (ie header) in a specific embodiment of the present application. The 1-bit identification bit "STEC TYPE (the name is just an example, there is no restriction in actual applications)" added to the header is to enable the user (at the user terminal) to actively know that the "quality factor data" is 6 bits when using it Or 1bit; specifically, the function of "STEC TYPE" is when this field is "1", it indicates that the "quality factor data (QI _B )" in the SSR information following this header is 1 bit in length; the same applies when this field is "0" indicates that the "quality factor data (QI _A )" in the SSR information following this message header is 6 bits in length.

1bit and 6bits in Fig. 2 are only specific examples of the quality factor data length, which can be adjusted according to the actual application, for example, it can be 2bits or 6bits, 3bits and 6bits, etc. Optionally, the A bit quality factor data is full quality factor data, and the B bit quality factor data is incremental quality factor data.

Optionally, the B-bit quality factor data is an identifier indicating the current quality factor data change. For example, the B bit is "1bit", where 1bit is an identifier 1 or 0 indicating the current quality factor data change, the identifier 1 indicates a decrease, and the identifier 0 indicates an increase. In another embodiment, the B-bit quality factor data is an increment of the current quality factor data.

Optionally, the sending system of the differential correction data message further includes a first receiving module and a calculation module. The first receiving module is used to receive the state space representation method correction data broadcast by the satellite in each information period, and the calculation module is used to perform encoding format calculation on the state space representation method correction data to generate a corresponding first differential correction data message Or the quality factor data in the second differential correction data message.

The first embodiment is a method embodiment corresponding to this embodiment. The technical details in the first embodiment can be applied to this embodiment, and the technical details in this embodiment can also be applied to the first embodiment.

The third embodiment of the present application relates to a method for receiving a differentially corrected data message, and its flow is shown in FIG. 4. The method for receiving a differentially corrected data message includes the following steps:

In step 401, the user terminal receives a differential correction data message from the server.

Optionally, the differential correction data message further includes satellite identification data, first, second, third and fourth model polynomial coefficient data (C ₀₀ , C ₀₁ , C ₁₀ , C ₁₁ ), wherein the first, The second, third, and fourth model polynomial coefficient data correspond to one piece of the quality factor data (QI _A or QI _B ).

Then, in step 402, the user terminal determines whether the quality factor data received in the differential correction data message is A bit or B bit, where A>B, and A and B are positive integers.

Optionally, in this step 402, the user terminal recognizes whether the quality factor data is an A bit or a B bit according to the identification bit in the header of the data packet based on the differential correction.

If the received quality factor data is A bit, then go to step 403, update the current quality factor data to the A bit quality factor data. For example, you can directly replace the current quality factor data with the A bit quality factor data

If the received quality factor data is B bits, then step 404 is entered to update the current quality factor data according to the current quality factor data and the B-bit quality factor data. For example, the B-bit quality factor data can be superimposed on the current quality factor data as an increment

Optionally, the A bit quality factor data is full quality factor data, and the B bit quality factor data is incremental quality factor data.

There are multiple methods for setting the quality factor data of the B bits. Optionally, the B-bit quality factor data is an identifier indicating the current quality factor data change, and the user terminal according to the pre-appointed variable and the B-bit received from the server, for example, 1bit, which may indicate the current An identification 1 or 0 for quality factor data change, identification 1 means decrease, and identification 0 means increase, to fix the current (for example, the last time received) quality factor data (QI value) according to the pre-arranged agreement through the communication protocol To choose to increase or decrease its absolute value. Optionally, the B-bit quality factor data is an increment of the current quality factor data.

It should be noted that the method for receiving a differential correction data message in the third embodiment of the present application may be a method for sending a differential correction data message corresponding to the first embodiment.

The fourth embodiment of the present application relates to a receiving system for differentially corrected data messages, and its structure is shown in FIG. 5. The receiving system for differentially corrected data messages includes a second receiving module, a judgment module, and a processing module.

The receiving module involved in this embodiment is used to receive the differential correction data message from the server.

The decision module involved in this embodiment is used to determine whether the quality factor data received in the differential correction data message is A bit or B bit, where A>B, and A and B are positive integers.

Optionally, the judgment module is further configured to correct the identification bit in the header of the data message according to the difference, and identify whether the quality factor data is A bit or B bit.

Optionally, the A-bit quality factor data (QI _A ) is full quality factor data, and the B-bit quality factor data (QI _B ) is incremental quality factor data.

Optionally, the B-bit quality factor data is an identifier indicating the current quality factor data change, or the B-bit quality factor data is an increment of the current quality factor data.

The processing module involved in this embodiment is used to update the current quality factor data to the A bit quality factor data if the received quality factor data is A bit, for example, the current quality factor data can be directly replaced with the A bit If the received quality factor data is B bits, update the current quality factor data according to the current quality factor data and the B-bit quality factor data. For example, the B-bit quality factor data can be used as The increment is superimposed on the current quality factor data as the updated quality factor data.

Optionally, the B-bit quality factor data is an identifier indicating the current quality factor data change, and the user terminal according to the pre-appointed variable and the B-bit received from the server, for example, 1bit, which may indicate the current An identification 1 or 0 for quality factor data change, identification 1 means decrease, and identification 0 means increase, to fix the current (for example, the last time received) quality factor data (QI value) according to the pre-arranged agreement through the communication protocol To choose to increase or decrease its absolute value. Optionally, the B-bit quality factor data is an increment of the current quality factor data.

The third embodiment is a method embodiment corresponding to this embodiment. The technical details in the third embodiment can be applied to this embodiment, and the technical details in this embodiment can also be applied to the third embodiment.

The following is a brief introduction to some related technologies involved in the implementation of this application:

The sending and/or receiving of the differential correction data message in this application is based on the RTCM standard message format, and refers to the format of the Japanese QZSS system (see pages 3 and 4), which is compatible with the existing and available GNSS systems The revised data has been arranged and compressed in a targeted manner.

GPS differential protocol and differential telegram algorithm are two issues that the differential system must consider. In a differential positioning application system, a large number of differential messages must be transmitted between the positioning terminal and the differential station. Since the positioning terminal is often a high-speed mobile target, in order to establish a data channel between the positioning terminal and the differential station, the traditional method is to use wireless communication. (Such as shortwave or ultrashortwave), the bottom interface usually adopts serial port (RS232/422), and the two parties communicate in byte mode. In order to adapt to this communication mode and realize the basic requirements of high efficiency and error control, the international standard RTCM 10403.2 has been formulated . With the continuous development of communication means, a large number of network methods are used to establish data links between the positioning terminal and the differential station. The data of the network communication is exchanged according to the data packet, and the errors are effectively controlled at the data link layer, and the price is low. Error, high-efficiency, and high-speed network communication brings new development opportunities to differential positioning applications. In order to adapt to the characteristics of network transmission, the RTCM 10403.1 standard has been formulated internationally and the network is now the main method.

The RTCM protocol specification includes application layer, presentation layer, transport layer, data link layer and physical layer. The most important thing for encoding and decoding is the arrangement at the physical layer. In the arrangement of the physical layer, its data volume directly has a key impact on the overall information transmission volume per unit time. In the case of unable to connect to the network, receiving satellite signals to obtain correction data has become the mainstream method. How to complete the transmission efficiently and quickly within the limited satellite transmission rate/time has become a top priority.

In the PPP-RTK joint positioning technology, the information is divided into three layers: SSR1, SSR2, and SSR3. Among them, SSR1 contains correction number categories: orbit-4068.2, clock offset-4068.3, code deviation-4068.4. SSR2 includes correction number categories: phase deviation -4068.5, global ionospheric correction number (VTEC). SSR3 includes the types of corrections: regional atmospheric corrections (regional ionospheric STEC-4068.8; regional ionospheric residual RC-4068.9; regional atmospheric correction Tropo-4068.9). The SSR information format name and transmission interval information broadcasted by the satellite base are shown in Table 1:

Table 1

This application mainly optimizes the arrangement of the field content in the SSR information (including SSR1, SSR2, and SSR3) in the differential correction data message. The RTCM code and the compact SSR code of QZSS correspond to a valid area (Network) basically in the range of 100km*100km, that is, 1 Network=10,000 square kilometers area. The traditional encoding format data is calculated as shown in Table 2:

Table 2

It can be seen from Table 2 above that in traditional coding, for each visible satellite of each GNSS system (a total of GPS, GLONASS, Galileo, Beidou, QZSS, etc.), the corresponding four coefficients (C ₀₀ , C ₀₁ , C ₁₀ , C ₁₁ ) and a quality indicator (Quality Indicator-QI) corresponding to the four coefficients. For each transmission, the traditional data volume of this SSR information is 6 bits. Calculated according to China's 9.6 million square kilometers, the number of Networks is 960 (refer to the above-mentioned 100km*100km as the area of a single area), and the data volume of a single transmission of this message is: 6*960=5760bits. This 6bits passes the following conversion formula (1):

Then a mapping table can be obtained, as shown in the SSRQI conversion table in Table 3:

table 3

CLASSCLASS	VALUEVALUE	IndexIndex	SSR QISSR QI
77	77	6363	5466.50<SSR QI5466.50<SSR QI
77	66	6262	4919.75<SSR QI≤5466.504919.75<SSR QI≤5466.50
77	55	6161	4373.00<SSR QI≤4919.754373.00<SSR QI≤4919.75
77	44	6060	3826.25<SSR QI≤4373.003826.25<SSR QI≤4373.00
77	33	5959	3279.50<SSR QI≤3826.253279.50<SSR QI≤3826.25
77	22	5858	2732.75<SSR QI≤3279.502732.75<SSR QI≤3279.50
77	11	5757	2186.00<SSR QI≤2732.752186.00<SSR QI≤2732.75

According to the binary code, we know: 3bits data can represent 8 states, that is, from 000 to 111. Since Class and Value are 3 bits each, there are 8*8=64 combinations, and the specific value of SSR QI can be obtained after conversion.

However, if every 4068 type of message requires a QI value, the total data volume will increase a lot, putting pressure on the channel, as shown below: If you calculate according to the 4068.1-4068.10 messages, each message has 6 bits per satellite QI value, the full QI value is:

6*80 (the number of satellites in the four GNSS systems) * 10 (the current message type) * 960 (Network) = 4,608,000bits

Compared with the content of a single message type, the amount of data is extremely huge. According to this calculation, the requirements for satellite communication resources (the rate is usually 1200bits to 2400bits per second) are extremely high, because the particularity of the 4068 information is that the data itself has a certain timeliness, and the longer the interval, the worse the correction effect. The solid compression of this format significantly improves the overall satellite positioning results.

In order to better understand the technical solutions of the present application, the following description will be given with a specific example. The details listed in the example are mainly for ease of understanding and are not intended to limit the protection scope of the present application.

The various embodiments of this application are applied to the northern China. The arrangement in the northern region can take the following forms:

In the northern region, the range of SSR information in the differential correction data message is less fluctuating. For example (every 30s from 2.5TECU to 2.45TECU), the full 6bits of Class and Value are transmitted during the first transmission, and only the increment is transmitted in the subsequent (The value of positive and negative fluctuations) instead of full amount An example of a new arrangement of SSR information in Table 4 below:

Table 4

Compared with Table 2, the optional 6bits or 1bit is added in Table 4. The user terminal will calculate the last received QI value according to the previously agreed variable and the received bit (1 ID is reduced, 0 ID is increased) Choose to increase or decrease the absolute value of the fixed amount agreed by the communication protocol in advance. The absolute value of 6bits will be broadcast uniformly in a fixed cycle (for example: every 10 information cycles is a fixed broadcast cycle, that is, the first and tenth times are full broadcast, and the rest are broadcast in 1bit optimized format) to enable new services to be added The terminal gets the original amount. Therefore, not only the user accuracy of the user is guaranteed, but also a certain amount of information compression is guaranteed. The compressed data amount is:

2*80 (the number of satellites in the four GNSS systems) * 10 (the current message type) * 960 (Network) = 1,356,000 bits

The 1,356,000bits is reduced to about one-third of the previous data volume of 4,608,000bits. Today, when satellite throughput is so cherished and the price is so high, the advantages of this saved resource are self-evident.

Page 1, Page 2, Page 3 and Page 4 in this manual are specifically:

Webpage 1: http://www.rtcm.org/differential-global-navigation-satellite--dgnss--standards.html;

Webpage 2: http://qzss.go.jp/en/technical/download/pdf/ps-is-qzss/is-qzss-l6-001.pdf;

Web page 3: http://qzss.go.jp/en/technical/download/pdf/ps-is-qzss/is-qzss-l6-001.pdf;

Page 4: http://qzss.go.jp/en/technical/ps-is-qzss/ps-is-qzss.html.

It should be noted that those skilled in the art should understand that the implementation functions of the modules shown in the implementation of the above-mentioned differentially corrected data message receiving system or sending system can refer to the aforementioned differentially corrected data message receiving system or sending method. The relevant description and understanding. The functions of the modules shown in the above embodiments of the receiving system or sending system of the differentially corrected data message can be realized by a program (executable instruction) running on a processor, or can be realized by a specific logic circuit. If the receiving system or sending system of the aforementioned differential correction data message in the embodiment of the present application is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application essentially or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for A computer device (which may be a personal computer, a server, or a network device, etc.) executes all or part of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, Read Only Memory (ROM, Read Only Memory), magnetic disk or optical disk and other media that can store program codes. In this way, the embodiments of the present application are not limited to any specific hardware and software combination.

Correspondingly, the embodiments of the present application also provide a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, the method implementations or implementations in the first embodiment of the present application are implemented. Each method is implemented in the third embodiment of this application. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be realized by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disc (DVD) or other optical storage, Magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media can be used to store information that can be accessed by computing devices. According to the definition in this article, computer-readable storage media does not include transitory media, such as modulated data signals and carrier waves.

In addition, the embodiment of the present application also provides a device for sending a differentially corrected data message, which includes a memory for storing computer-executable instructions, and a processor; the processor is used to execute the computer-executable instructions in the memory The steps in each method implementation manner in the above-mentioned first embodiment are realized at the time. Among them, the processor can be a central processing unit (Central Processing Unit, "CPU"), other general-purpose processors, digital signal processors (Digital Signal Processor, "DSP"), and application specific integrated circuits (Application Specific Integrated Circuits). Integrated Circuit, referred to as "ASIC"), etc. The aforementioned memory may be a read-only memory (read-only memory, "ROM"), random access memory (random access memory, "RAM"), flash memory (Flash), hard disk or solid state hard disk, etc. The steps of the methods disclosed in the various embodiments of the present invention may be directly embodied as executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

The embodiment of the present application also provides a device for receiving a differentially corrected data message, which includes a memory for storing computer-executable instructions, and a processor; the processor is used to implement when the computer-executable instructions in the memory are executed The steps in each method implementation in the third embodiment described above. Among them, the processor can be a central processing unit (Central Processing Unit, "CPU"), other general-purpose processors, digital signal processors (Digital Signal Processor, "DSP"), and application specific integrated circuits (Application Specific Integrated Circuits). Integrated Circuit, referred to as "ASIC"), etc. The aforementioned memory may be a read-only memory (read-only memory, "ROM"), random access memory (random access memory, "RAM"), flash memory (Flash), hard disk or solid state hard disk, etc. The steps of the methods disclosed in the various embodiments of the present invention may be directly embodied as executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

It should be noted that in the application documents of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these There is any such actual relationship or sequence between entities or operations. Moreover, the terms "include", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also includes Other elements of, or also include elements inherent to this process, method, article or equipment. If there are no more restrictions, the element defined by the phrase "including one" does not exclude the existence of other same elements in the process, method, article, or equipment including the element. In the application documents of this patent, if it is mentioned that an act is performed based on a certain element, it means that the act is performed at least based on that element, which includes two situations: performing the act only based on the element, and performing the act based on the element and Other elements perform the behavior. Multiple, multiple, multiple, etc. expressions include two, two, two, and two or more, two or more, and two or more expressions.

All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as a basis for modification when necessary. In addition, it should be understood that the above descriptions are only preferred embodiments of this specification, and are not intended to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of this specification shall be included in the protection scope of one or more embodiments of this specification.

Claims

A method for sending a differential correction data message is characterized in that it includes:

The server broadcasts the first differential correction data message to the user terminal in the first information period, and the number of bits occupied by the quality factor data in the first differential correction data message is A;

At least one continuous information period after the first information period, the server broadcasts a second differential correction data message to the user terminal, the bits occupied by the quality factor data in the second differential correction data message The number of bits is B, where A>B, and A and B are positive integers.
The method for sending a differentially corrected data message according to claim 1, wherein the header of the differentially corrected data message includes an identification bit for indicating the bits occupied by the quality factor data in the message The number of bits is A bit or B bit.
The method for sending a differential correction data message according to claim 1, wherein the first differential correction data message further includes satellite identification data, and first, second, third, and fourth model polynomial coefficient data , Wherein the quality factor data in the first differential correction data message corresponds to the first, second, third, and fourth model polynomial coefficient data in the first differential correction data message;

The second differential correction data message further includes satellite identification data, first, second, third and fourth model polynomial coefficient data, wherein the quality factor data in the second differential correction data message corresponds to the The second difference corrects the first, second, third and fourth model polynomial coefficient data in the data message.
The method for sending a differential correction data message according to claim 1, wherein the quality factor data in the first differential correction data message is full quality factor data, and the second differential correction data message The quality factor data in is incremental quality factor data.
The method for sending a differential correction data message according to claim 1, wherein the quality factor data in the second differential correction data message is an increment of the current quality factor data.
The method for sending a differential correction data message according to any one of claims 1-5, wherein before the server broadcasts the first differential correction data message to the user terminal in the first information period, the method further comprises :

The server receives the state space representation method correction data broadcast by the satellite in each information cycle;

The server performs encoding format calculation on the state space representation method correction data to generate corresponding quality factor data in the first differential correction data message or quality factor data in the second differential correction data message.
A sending system for differentially corrected data messages is characterized in that it comprises:

The first sending module is configured to broadcast a first differential correction data message to the user terminal in a first information period, and broadcast a second differential data message to the user terminal at least one continuous information period after the first information period A corrected data message, where the number of bits occupied by the quality factor data in the first differentially corrected data message is A, and the number of bits occupied by the quality factor data in the second differentially corrected data message is B, and A >B, A and B are positive integers.
The sending system of a differentially corrected data message according to claim 7, wherein the header of the differentially corrected data message includes an identification bit for indicating the bits occupied by the quality factor data in the message The number of bits is A bit or B bit.
The sending system of a differential correction data message according to claim 7, wherein the first differential correction data message further includes satellite identification data, and first, second, third, and fourth model polynomial coefficient data , Wherein the quality factor data in the first differential correction data message corresponds to the first, second, third, and fourth model polynomial coefficient data in the first differential correction data message;

The second differential correction data message further includes satellite identification data, first, second, third and fourth model polynomial coefficient data, wherein the quality factor data in the second differential correction data message corresponds to the The second difference corrects the first, second, third and fourth model polynomial coefficient data in the data message.
The sending system of a differential correction data message according to claim 7, wherein the quality factor data in the first differential correction data message is full quality factor data, and the second differential correction data message The quality factor data in is incremental quality factor data.
8. The sending system of a differential correction data message according to claim 7, wherein the quality factor data in the second differential correction data message is an increment of the current quality factor data.
8. The system for sending differential correction data messages according to any one of claims 7-11, further comprising a first receiving module and a calculation module;

The first receiving module is configured to receive state space representation method correction data broadcast by satellites in each information period, and the calculation module is configured to perform encoding format calculation on the state space representation method correction data to generate the corresponding first The quality factor data in the differential correction data message or the quality factor data in the second differential correction data message.
A method for receiving a differentially corrected data message is characterized in that it includes:

The user terminal receives the differential correction data message from the server;

The user terminal determines whether the quality factor data received in the differential correction data message is A bit or B bit, where A>B, and A and B are positive integers;

If the received quality factor data is an A bit, update the current quality factor data to the A bit quality factor data;

If the received quality factor data is B bits, the current quality factor data is updated according to the current quality factor data and the B-bit quality factor data.
The method for receiving a differentially corrected data message according to claim 13, wherein the user terminal determines whether the quality factor data received in the differentially corrected data message is A bit or B bit, so The user terminal recognizes whether the quality factor data is A bit or B bit according to the identification bit in the header of the differential correction data message.
The method for receiving a differential correction data message according to claim 13, wherein the A-bit quality factor data is full quality factor data, and the B-bit quality factor data is incremental quality factor data.
The method for receiving a differential correction data message according to any one of claims 13-15, wherein the B-bit quality factor data is an increment of the current quality factor data.
A receiving system for differentially corrected data messages is characterized by comprising:

The second receiving module is used to receive the differential correction data message from the server;

A judgment module, configured to determine whether the quality factor data received in the differential correction data message is A bit or B bit, where A>B, and A and B are positive integers;

The processing module is configured to update the current quality factor data to the A bit quality factor data if the received quality factor data is A bit, and if the received quality factor data is B bit, then according to The current quality factor data and the B-bit quality factor data update the current quality factor data.
The receiving system of a differential correction data message according to claim 17, wherein the judgment module is further configured to identify the quality factor data according to the identification bit in the header of the differential correction data message It is A bit or B bit.
The system for receiving a differential correction data message according to claim 17, wherein the A-bit quality factor data is full quality factor data, and the B-bit quality factor data is incremental quality factor data.
The system for receiving a differentially corrected data message according to any one of claims 17-19, wherein the B-bit quality factor data is an increment of the current quality factor data.
A device for sending a differential correction data message is characterized in that it comprises:

Memory for storing computer executable instructions; and,

The processor is configured to implement the steps in the method according to any one of claims 1 to 6 when executing the computer executable instructions.
A computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, the computer-readable The steps in the method described.
A receiving device for differentially corrected data messages is characterized by comprising:

Memory for storing computer executable instructions; and,

The processor is configured to implement the steps in the method according to any one of claims 13 to 16 when executing the computer executable instructions.
A computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, the computer-readable The steps in the method described.